1. Field of the Invention
The present invention relates to a wedge-base lamp and socket assembly for use as lightning devices for vehicles and more particularly, to an assembly of a wedge-base lamp (without its plug) and a socket, which assembly ensures fool-proof coupling between different types of wedge-base lamps and sockets.
2. Description of the Related Art
Conventionally, double filament lamps such as vehicle stop-tail lamps have not been used in the form of a wedge-base type lamp. The reason for this is that means for preventing erroneous coupling between different types of wedge-base lamps and sockets have not been provided heretofore, contrary to the coupling between lamps with their specific plugs and corresponding sockets.
Since plugs are not necessary for wedge-base lamps, the number of manufacturing steps thereof is reduced and the material for plugs are dispensed with, thus resulting in cost effectiveness. Double filament type wedge-base lamps have long been desired in consideration of the above advantageous effects. Although single filament type wedge-base lamps are prevailing in the art, double filament type wedge-base lamps are not available in the market because of the lack of proper means for preventing erroneous coupling.